Tsunami Wall of Water Risk Known to Engineers, Regulators

Smoke is seen rising from the building housing No. 3 reactor at Tokyo Electric Power Co.'s Fukushima Dai-Ichi nuclear power plant in Okuma town, Fukushima prefecture, Japan, in this handout photograph released to the media on March 21, 2011. Source: Tokyo Electric Power Co. via Bloomberg

March 28 (Bloomberg) -- Japan’s nuclear regulators and the
operator of the crippled Fukushima reactors were warned that a
tsunami could overwhelm the plant’s defenses and failed to
recognize the threat.

The Trade Ministry dismissed evidence two years ago from
geologists that the power station’s stretch of coast was overdue
for a giant wave, minutes from a government committee show.
Tokyo Electric Power Co. engineers also didn’t heed lessons from
the 2004 tsunami off Indonesia that swamped a reactor 2,000
kilometers (1,200 miles) away in India, even as they advised the
nuclear industry on coping with the dangers.

Tokyo Electric’s Dai-Ichi plant withstood the impact of
Japan’s record earthquake March 11, only for a wall of water to
knock out generators needed to keep its reactors cool. The cost
of the miscalculation mounted as explosions and fires at the
plant caused radiation leaks that forced the evacuation of more
than 200,000 people and contaminated drinking water.

“The Japanese system underestimated the natural threat
from the earthquake and tsunami,” said Pierre Zaleski of
University Paris Dauphine and a former French Atomic Energy
Commission member. “They really haven’t taken these threats
seriously enough, and they haven’t moved fast enough.”

Underscoring the Japanese government’s failure to foresee
the risk posed by tsunamis to nuclear power plants is the
country’s national report on nuclear safety, filed with the
International Atomic Energy Agency in September 2010.
The 194-page document discusses detailed earthquake mitigation
measures 74 times. Tsunamis are mentioned twice, both times in
reference to a working group studying the issue.

Tokyo Electric’s sea-wall defenses for the Dai-Ichi plant
were built under the assumption that the coastline on which it
sat wasn’t prone to tsunamis higher than 5.5 meters, said
Yoshimi Hitosugi, a Tokyo-based company spokesman.

Historical Precedent

An 8-meter tsunami that hit Japan’s northeast in 869 swept
as far as 4 kilometers inland at Sendai Bay, stretching south
toward the Dai-Ichi plant, according to at least half a dozen
scientific studies spanning more than a decade.

A repeat could occur soon because sediment samples showed
the tsunami had a pattern of recurring every 800 to 1,000 years,
according to a 2001 report by a research team funded by the
government’s Science Ministry.

Minutes of a committee meeting held by the Trade Ministry
to assess reactor safety on June 24, 2009, show that Yukinobu
Okamura, who heads the government-funded Active Fault and
Earthquake Research Center, asked Tokyo Electric why it hadn’t
taken on board evidence of the tsunami risk.

Debate Cut

The debate was cut short by an official from the regulator,
Nuclear and Industrial Safety Agency, who said the matter needed
study. The agency approved the safety report a month later,
calling on Tokyo Electric to “take appropriate measures” to
adopt lessons from research on tsunami risk.

“The utility bears some responsibility for this, but the
regulator didn’t give any guidance,” Okamura said in a March 23
phone interview. “Looking back, I wish I had pressed harder.
It’s easy to say after the fact.”

The committee’s focus was on the impact of earthquake
vibration and it was turning to tsunamis after, said Yuji
Wakamatsu, a spokesman for the nuclear safety agency.

Tokyo Electric engineers were looking at tsunami risk at
least as far back as 2005.

The tsunami caused by the December 2004 earthquake off the
Indonesian island of Sumatra led to a conference in Tamil Nadu,
India, hosted by Kalpakkam nuclear station, which had survived a
direct hit.

Tsunami Advice

At the August 2005 forum, Tokyo Electric senior nuclear
engineer Toshiaki Sakai delivered a report called “Tsunami
Evaluation Method for Nuclear Power Stations in Japan,”
according to the IAEA’s website. The company declined to make
him available for an interview and Hitosugi said it cannot find
the report.

Japan’s delegation gave guidance on coping with tsunami
threats and developed a system to evaluate risks and protect
reactors, the IAEA said in a report from the conference on its
website.

The lesson from the Kalpakkam plant was simple: build high,
said S. Krishnamurthy, executive director of operations at
Nuclear Power Corp. of India, who was in charge at the time.

“Kalpakkam has been built in such a way that almost all
its units, except of course the pump house that pumps sea water,
are at an elevation,” he said last week.

Onagawa Too

Tohoku Electric Power Co.’s Onagawa nuclear power plant was
about 75 kilometers closer to the epicenter of the quake, and
suffered no critical damage because it was built 15 meters above
sea level, spokesman Yoshitake Kanda said.

In both instances, reactors were safely shut down and
cooling systems continued to operate.

Tohoku Electric said it’s strengthening preparations
against disasters, including keeping a generator car at its
nuclear plants at all times in case of power failures, according
to a statement yesterday on the utility’s website.

In 2009, Japan’s Nuclear Safety Commission listed the
“Seismic Roadmap” as one of its key priorities, with an
emergency preparedness program for tsunami as one of the mid-term plans it was working on between 2007 and 2012, according to
the commission’s report from February 2009.

Kashiwazaki

Last November, Tokyo Electric hosted the first symposium on
seismic safety of nuclear installations at Kashiwazaki, home to
the world’s largest nuclear plant which was shut down after a
2007 earthquake caused a fire and spillage of radioactive water.
One of four main sessions was on tsunamis, during which IAEA’s
Kenta Hibino made a presentation on the global nuclear
community’s “work plan for tsunami hazard.”

The IAEA declined to set up an interview with Hibino,
saying all its experts were busy dealing with the crisis.

Japan has suffered 195 tsunamis since 400, according to
Japan’s Central Research Institute of Electric Power Industry,
which produced a report on tsunami threats to nuclear plants on
the opposite coast to Dai-Ichi in July 2008. Three in the past
three decades had waves of more than 10 meters.

A 7.6-magnitude quake in 1896 off the east coast of Japan
created waves as high as 38 meters, while an 8.6-magnitude
temblor in 1933 led to a surge as high as 29 meters, according
to the U.S. Geological Survey.

Geologist Masanobu Shishikura, a researcher under Okamura
who has focused on the 869 tsunami, said he wasn’t surprised
historical evidence wasn’t heeded to. When he presented to
government officials from two towns on the coast north of Dai-Ichi, the urgency wasn’t clear even to him.

Today, those towns of Higashi Matshushima and Ishinomaki
lie in ruins.

“At the time, we thought it was unfortunate they didn’t
take us seriously, but we figured it was just a matter of making
a better presentation,” Shishikura said. “If only the tsunami
had waited a little longer, we might have been ready.”